From a50777c791031d7345ce95785ea6220f67339d90 Mon Sep 17 00:00:00 2001 From: Dan Magenheimer Date: Fri, 8 Jul 2011 12:26:21 -0600 Subject: xen: tmem: self-ballooning and frontswap-selfshrinking This patch introduces two in-kernel drivers for Xen transcendent memory ("tmem") functionality that complement cleancache and frontswap. Both use control theory to dynamically adjust and optimize memory utilization. Selfballooning controls the in-kernel Xen balloon driver, targeting a goal value (vm_committed_as), thus pushing less frequently used clean page cache pages (through the cleancache code) into Xen tmem where Xen can balance needs across all VMs residing on the physical machine. Frontswap-selfshrinking controls the number of pages in frontswap, driving it towards zero (effectively doing a partial swapoff) when in-kernel memory pressure subsides, freeing up RAM for other VMs. More detail is provided in the header comment of xen-selfballooning.c. Signed-off-by: Dan Magenheimer [v8: konrad.wilk@oracle.com: set default enablement depending on frontswap] [v7: konrad.wilk@oracle.com: fix capitalization and punctuation in comments] [v6: fix frontswap-selfshrinking initialization] [v6: konrad.wilk@oracle.com: fix init pr_infos; add comments about swap] [v5: konrad.wilk@oracle.com: add NULL to attr list; move inits up to decls] [v4: dkiper@net-space.pl: use strict_strtoul plus a few syntactic nits] [v3: konrad.wilk@oracle.com: fix potential divides-by-zero] [v3: konrad.wilk@oracle.com: add many more comments, fix nits] [v2: rebased to linux-3.0-rc1] [v2: Ian.Campbell@citrix.com: reorganize as new file (xen-selfballoon.c)] [v2: dkiper@net-space.pl: proper access to vm_committed_as] [v2: dkiper@net-space.pl: accounting fixes] Cc: Jan Beulich Cc: Jeremy Fitzhardinge Cc: --- include/xen/balloon.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include/xen/balloon.h') diff --git a/include/xen/balloon.h b/include/xen/balloon.h index a2b22f0..4076ed7 100644 --- a/include/xen/balloon.h +++ b/include/xen/balloon.h @@ -23,3 +23,13 @@ void balloon_set_new_target(unsigned long target); int alloc_xenballooned_pages(int nr_pages, struct page** pages); void free_xenballooned_pages(int nr_pages, struct page** pages); + +struct sys_device; +#ifdef CONFIG_XEN_SELFBALLOONING +extern int register_xen_selfballooning(struct sys_device *sysdev); +#else +static inline int register_xen_selfballooning(struct sys_device *sysdev) +{ + return -ENOSYS; +} +#endif -- cgit v1.1